Vol. XIII. August, i go 'j. No. j. 



BIOLOGICAL BULLETIN 



THE INFLUENCE OF THE AMOUNT OF INJURY 

 UPON THE RATE AND AMOUNT OF RE- 

 GENERATION IN MANCASELLUS 

 MACROURUS (GARMAN). 1 



MAX M. ELLIS. 



I. Introduction. 



Until Dr. Zeleny announced the results of his experiments on 

 the fiddler crab, Gelasimus, and the brittle star, Ophioglypha, it 

 was generally thought that an increase in the amount of injury 

 would decrease the ability to repair injury, that is, it would re- 

 tard regeneration. In these two forms he found that an increase 

 in the degree of injury produced a corresponding increase in the 

 rate of regeneration. Later he established the same principle as 

 true for the common crawfish, 2 Cambarus propinquus. 



From the crawfish experiment he concludes that "in series 

 with the greater degree of injury each chela regenerates more 

 rapidly than the single removed chela of the series with the lesser 

 degree of injury." These three experiments present the idea 

 that an increase in the amount of injury accelerates rather than 

 retards regeneration. However, it is probable, as is indicated by 

 Dr. Zeleny's work on the brittle star, that there is a degree of 

 injury, a limit, beyond which this is not the case. In the work 

 just mentioned, 3 when all five of the arms were removed the 

 regeneration was slower than when four were removed. 



The present experiments were made with the object of con- 

 tributing some quantitative data concerning the relation of the 

 amount of injury to the rate and amount of regeneration. The 



1 Contribution from the Zoological Laboratory of Indiana University. No. 85. 

 ijour. Ex. Zoo!., Vol. II., No. 3, '05. 

 3 Jour. Ex. Zool., Vol. II., No. 1. 



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